Function Codes Supported by Modbus TCP Slave

The Modbus TCP Slave Communications option supports the Modbus function codes listed in the following table. As well, the maximum number of coils or registers that may be specified or included in a single Modbus message is also given.

Function Code

Description

Maximum # of coils / registers

1

Read Coil Status

2000

2

Read Input Status

2000

3

Read Holding Registers

125

4

Read Input Registers

125

5

Force Single Coil

1

6

Force Single Register

1

15 (0x0F)

Force Multiple Coils

800

16 (0x10)

Preset Multiple Registers

100

More information

Modbus/TCP Slave protocol.